code: def test_duration(util):
      clip = TextClip(
          "hello world", size=(1280, 720), color="white", font=util.FONT
      )
      clip = clip.with_duration(5)
      assert clip.duration == 5
      clip.close()
  
      clip2 = clip.fx(blink, duration_on=1, duration_off=1)
      clip2 = clip2.with_duration(5)
      assert clip2.duration == 5
  
file_path: moviepy/tests/test_TextClip.py
imports: import os
  import numpy
  import pytest
  from moviepy.video.fx.blink import blink
  from moviepy.video.VideoClip import TextClip
label_desc: Use image node_id 3 for calling a global function with example usage: test_duration(util) without return types